Radioactive Contamination in Steel Products – Indian Experience

Khaidem Ranjankumar Singh

Radiological Safety Division

Atomic Energy Regulatory Board

Anushaktinagar

Mumbai – 400 094, IndiaE-mail: rksingh@aerb.gov.in, rk.aerb@gmail.com

Outlines of the Talk

1. Radioactive contamination

2. Incidents of radioactive contamination in steel

products

3. Radiological impact of contamination

4. Economical Impact of contamination

5. Preventive measures adopted in India

6. Suggested action plan at the international level

7. Conclusion

Radioactive contamination

What is radioactive contamination in steel ?

- is it anything showing radiation level above natural background radiation level ?

- is it anything above the exempt (activity concentration and total activity) level of IAEA ?

- is it any other ?

Incidents of radioactive contamination

First incident reported in 1991About 12 incidents, either reported to and during inspection by AERBMain radioisotope of contamination is Co-60 of industrial use, category 3 and below sourcesObserved radiation levels are 0.06 to 250 µSv/h, LSA IMetals identified contaminated are rods, flanges, valves, door pull handles, man hole covers, nails, coils, bright bars, billets etc.No report of any serious health hazard so farUse of imported metal scrapMost of the contaminated material identified since the last two/three years lying pending for safe disposal

Radiological impact of contamination

Attempted to estimate the dose that might be received by a worker in a typical Indian foundry, which is very conservative. Based on the actual measurement of radiation level for a contaminated steel bundle(30 nos. of SS bars, 6 m length, dia 20 mm and total mass of 465 kg).Measured radiation levels are at

the centre of the surface of the bundle - 484. 66 µSv/ha distance of 30 cm - 288.47 µSv/ha distance of 60 cm - 187.05 µSv /ha distance of 1.5 m - 74.16 µSv /ha distance of 2.5 m - 35.20 µSv /ha distance of 3 m - 24.23 µSv /h

Beyond 3 m distance, inverse square law can be applied.

Radiological impact contd.

Negligible

0.145 mSv

0.194 mSv

234.7 µSv

58.3 µSv

2.4 mSv

0.97 mSv

42.6 µSv

510 µSv

1.21 mSv

187.1 µSv

0.0142 Person-Sievert

Unloading of scrap

Melting

Refining through Argon Oxygen De-carbonization (AOD)

Continuous casting

Cooling

Painting

Length measurement

End cutting

Surface grinding

Storage

Loading on the truck for shipment

Estimated collective dose( about 22 workers)

Estimated dose receivedStages of process

Economical impact of contamination.

Calculation based

on the inputs received from an Indian exporter

material steel grade 304 exported to an European destination and returned to India after detection of contamination at the port of destination

Price index prevailed in steel market in Aug , 2008.

Economical impact contd.2 Some carriers have policy of not taking back the containers

having contained contaminated material.

3 Assuming the current rate of foreign exchange US $ 1 = Rs 48

Exorbitantly high transport charge for return of contaminated material to the country of origin

Suitable shipping carriers are not easily available

May delay the shipment, and sometimes deter the exporter to bring back contaminated material to avoid bankruptcy.

Preventive measures adopted in India

Held consultative meeting with Engineering Export Promotion Council (EEPC), government supported conglomeration of the manufacturers and exporters of engineeringproduct to create awareness and find ways of avoiding contamination of steel products.

Several informative articles published in the news bulletin of EEPC on prevention of radioactive contamination of steel products.

Five awareness programmes on radiation safety conducted for the manufacturers, exporters and concerned government officials

Preventive measures adopted in India contd.

The manufacturer/exporters were advised to procure sensitive radiation monitoring instruments to monitor the incoming raw material and outgoing finished products

Officials of AERB conducted more than 70 random inspections of the foundries and warehouses involved with the manufacturing of steel products from scrap steel metal.

The concerned ministry of the Government of India has been requested to take up installation of portal monitors at the entry and exit points of all the international ports in the country. An indigenously developed portal monitor including neutron detectorhas been installed at Jawaharlal Nehru Port, Nava Sheva, the largest port in the country.

Preventive measures adopted in India contd.A notification has been issued through Indian Gazette that

every importer of metal scrap should obtain a certificate issued by the regulatory body or an agency accredited by the regulatory body in the country of export certifying that the metal scrap is free from radioactivity.

Strong regulatory control over the use of radiation sources.

Any loss, theft and abandonment of source thoroughly investigated; preventive measures taken up; and reported to IAEA through ITDB.

Any contamination incident brought to the notice of AERB, concerned manufacturers/exporters advised for ensuring safety and security of the contaminated material pending its final safe disposal at an authorized site.

Suggested action plan at the international level

Mandatory radiation monitoring of the incoming raw material and outgoing finished products in the steel factories using scrap metal as input material should be introduced through suitable national legislation.

A harmonized level of standards for acceptance of contamination in steel products should be developed.

Countries exporting scrap metal should also monitor the consignment before dispatch.

Concerned national regulatory authorities should strengthen the mechanism adopted for certifying radioactivity free of the steel materials meant for export and import.

Suggested action plan at the international level

Concerned national regulatory authorities should facilitate the segregation of the contaminated steel product at the port ofdetection; and allow only the contaminated material be returned to the country of origin while retaining the non-contaminated material for use in the importing country.

Concerned national regulatory authority should advise about the packaging of the contaminated material as per the IAEA regulations for the safe transport of radioactive material before returning the contaminated material to the country of origin andissue the necessary regulatory clearances to enable the return of the radioactively contaminated material.

Suggested action plan at the international level

Concerned national regulatory authority of the country of origin of contaminated material should issue necessary regulatory clearances to enable bringing back (import) of the radioactively contaminated material.

Concerned port authorities en-route the shipment of the contaminated material should issue prompt clearances for transitstops.

Denials of shipments of radioactively contaminated material by the shipping carriers should be taken up with the International Maritime Organization; and shipping carriers should be made aware of the fact that an empty freight container having contained radioactively contaminated steel material is not hazardous and can be continued to use as earlier.

Suggested action plan at the international level

An International Co-ordinating Committee be constituted for better exchange of information among all stake holders.

ConclusionRadioactive contamination is undesirable

Main cause is the presence of radioactive material in the metal scrap that is used by the scrap recycling industry.

Radiological hazard, generally, from such contamination is very low .

But, can have significant economic impact in the industry.

Necessary that all stakeholders take appropriate measures toprevent such incidents .

An action plan to tackle the problem at the international level needs to be considered.

Desirable that a harmonized level of standards for acceptance of contamination in steel products should be developed for the benefit of each country.

Challenges

Method for Safe disposal of bulky and voluminous radioactivecontaminated material.

Identifying of contaminated material already circulated in the domestic market.

Special thanks to Ms Lucila Ma Ramos, Chairwoman ofProgramme Committee

Mr. Jose Gill Martin , CSN

&

Mr. Didier Louvat, IAEAMr. Luis Jova Sed, IAEA